Researchers develope simple blood test to quickly recognize sarcoidosis

WASHINGTON: Researchers have developed a technique for quickly and cheaply identifying sarcoidosis, a chronic inflammatory illness characterized by the growth of microscopic lumps called granulomas in the lungs and other organs. The technique, which uses a simple blood test, may allow for the selective use of more intrusive diagnostic tests that are commonly employed to identify the disease. The results were reported in the American Journal of Respiratory and Critical Care Medicine.

"Currently, diagnosing sarcoidosis isn't a straightforward process and requires tissue removal and testing with additional screenings to rule out other diseases, such as tuberculosis or lung cancer," said James Kiley, Ph.D., director of the NIH's Division of Lung Diseases at the National Heart, Lung, and Blood Institute (NHLBI)."Using a blood test will help diagnose faster, particularly in those organs that are more challenging to biopsy and with less harm to the patient." Though the exact cause of sarcoidosis is unknown, researchers suspect it is an immune disorder triggered by a group of specific antigens, which are generally foreign substances that incite an immune response in the body. In the United States, an estimated 8-11 people per 100,000 are affected by sarcoidosis each year, according to previous research.

To identify antigens and determine which might be linked to sarcoidosis, scientists collected lung fluid samples and blood cells from patients with pulmonary sarcoidosis and then extracted the genetic material. Using a combination of molecular techniques, the researchers homed in on two newly described disease-specific antigen biomarkers that only bind to the antibodies of sarcoidosis-positive patients.

They next designed a highly specific blood test, which only requires a small amount of blood, to determine if they could accurately detect sarcoidosis. To verify the test, researchers compared blood samples from 386 people, which included patients with sarcoidosis, patients with tuberculosis, patients with lung cancer and healthy individuals.The researchers confirmed that their test was able to differentiate patients who had sarcoidosis from those with other respiratory diseases. "More testing needs to be completed before this screening method is ready for clinical use, but it's possible that could be a reality within a few years," said Samavati.

"Dr. Samavati's important work is an excellent example of how scientific research can have promising results that may lead to addressing major health challenges," said Ezemenari M. Obasi, Ph.D., vice president for research at Wayne State University."I look forward to the potential impact this research will have on the lives of those inflicted with sarcoidosis."